Metal containers have long enjoyed widespread acceptance and extensive use in the packaging industry for containing a wide variety of products ranging from food to automotive chemicals. Such containers have proven particularly suitable for containing volatile and carbonated liquids because of their ability to withstand high internal pressures while resisting migration of gas molecules through the container walls and into the atmosphere. Perhaps the best known and possibly most extensive use of such metal containers is the common aluminum beverage can used to contain and dispense carbonated soft drinks and beer.
While aluminum beverage cans have proven highly successful since their introduction and have undergone many improvements such as the easy-opening pop-top, they nevertheless have long been plagued with a persistent and heretofore unsuccessfully addressed problem inherent in their respective designs. Namely, once opened, the common beverage can is virtually impossible to reseal effectively against spoilage, contamination, and decarbonation of its contents. As a result, the entire beverage must either be consumed completely upon opening the can or discarded as unusable waste. The same problem plagues containers for other volatile liquids such as freon refrigerant often used to recharge automotive air conditioning systems.
As a consequence of the difficulty in resealing aluminum beverage and other cans, such cans have long been limited to single serving or single use sizes and metal container manufacturers have generally been unable to compete with makers of plastic and glass bottles in the growing and ever more lucrative markets for larger multiple serving or multiple use sized containers.
Prior attempts to provide means for resealing an opened aluminum can have included separate stoppers, purchased as accessories, that snap into the can opening in attempt to seal the can. While such stoppers represent a small step in the right direction, they nevertheless generally tend to be inconvenient and ineffective since they are easily lost and usually do not conform well to or seal effectively the can opening.
Other examples of devices for resealing opened containers are disclosed in Summers U.S. Pat. No. 3,610,306, Turner U.S. Pat. No. 4,180,178, and Thompson U.S. Pat. No. 4,856,667. While these devices can be somewhat useful for resealing non-pressurized containers, they generally are not intended nor are they suitable for resealing against internal pressures that can be generated within a partially filled carbonated beverage or volatile liquid container and therefore fail to address the problems discussed above.
Thus, a continuing and heretofore unaddressed need exists for an inexpensive and simple-to-use method and apparatus for closing and resealing effectively an opened beverage can or indeed any metal container of pressurized liquids and gasses. The present invention is such a method and apparatus.